US military to shoot down errant spy satellite

February 15, 2008 The United States military has announced their intention to use a missile to destroy USA-193, a spy satellite which failed immediately after launch in December 2006. Since launch, the satellite's orbit has decayed and it is approaching the point at which it will re-enter the atmosphere and potentially fall to Earth. The missile will be used as a kinetic anti-satellite weapon (ASAT), and will destroy the satellite through hitting it at high speed.

The satellite potentially has hazardous materials on board, including hydrazine. Ordinarily, the hydrazine would be used as fuel, but since the satellite failed immediately after launch, this was never used. It is expected that about half of the satellite would be capable of surviving re-entry, potentially including the fuel tank. Since hydrazine is toxic, the satellite could pose a severe danger if it hits in a populated area, however it has been considered likely that the tank would probably rupture and explode during re-entry. Destroying the satellite on the grounds of safety is the stated purpose of shooting down the satellite. Officials have denied claims that it is to prevent secrets that the satellite is carrying from falling into the wrong hands, or that it is a demonstration in response to a Chinese ASAT test in January 2007.

The missile which will be used to shoot down the satellite will be a Standard Missile 3 (SM-3), which will be launched from the USS Lake Erie in the North Pacific Ocean. The missile, which was designed to shoot down other missiles, will be modified slightly in order to allow it to recognise USA-193 as its target.

If the attack is successful, the satellite will be broken into many small pieces. This will eliminate the hazard from the hydrazine and break into small enough pieces that nothing will survive reentry. Officials reported that the likelihood of success was "high". NASA Administrator Michael Griffin said that it was impossible to make the situation any worse. Missing the satellite would change nothing, while a slight blow would still result in the satellite returning to Earth, and a direct hit would destroy the satellite. It is believed that the missile will be aimed directly at the satellite's fuel tank.

While the debris will not pass near enough to the International Space Station to cause disruption, it is not clear whether it could affect spacecraft passing through the lower orbit in which USA-193 currently resides. For this reason, the satellite will not be destroyed until the Space Shuttle Atlantis, which is currently conducting mission STS-122, has landed. The debris caused by the satellite's destruction is expected to re-enter the atmosphere within a few weeks.